Although regarded as a monotypic genus, Ellipsaria tends to land near Truncilla in phylogenetic studies (Campbell et al., 2005; Zanatta & Murphy, 2006). This is perhaps not too surprising. According to Ortmann (1912), the two genera differ in the size of their glochidia. While the larvae of Ellipsaria are "very large," those of Truncilla are "extremely small." Otherwise, characters of their soft-anatomy are similar.

We ran into a few "butterflies" while sampling on the Mississippi River earlier this summer. Though not Federally listed in the United States, E. lineolata is protected at the state level in Wisconsin, Minnesota, and Iowa in the Upper Midwest.